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The responses of cane toad (Bufo marinus) gametes, used as a model for the development of assisted reproduction techniques for rare and endangered amphibians, to short-term storage at temperatures > 0 degrees C were studied. Whole excised testes were stored at 0 degrees or 4 degrees C for 15 days, and sperm motility was measured at excision and after storage for 2, 5, 7, 10, 12 and 15 days. Spermatozoa showed > 50% motility for 7 days at 0 degrees C and for 5 days at 4 degrees C. At 15 days, only spermatozoa stored at 0 degrees C still showed some motility (3%). Sperm suspensions were prepared at 5 day intervals over 30 days in simplified amphibian ringer (SAR) at dilutions of 1:1, 1:5 and 1:10 (w/v) testes:SAR. Aliquots from each dilution were stored at 0 degrees C in Eppendorf tubes opened at 5 day intervals of storage (aerated) or kept sealed (unaerated) (treatments: aerated or unaerated; 5, 10, 15, 20, 25 and 30 days storage). After 30 days, sperm motility and fertilizing capacity were determined. The optimal protocol for sperm storage up to 10 days, as assessed by the retention of fertilizing capacity, was as a 1:5 testis:SAR (w/v) suspension, whereas the longest absolute retention of both motility and fertilizing capacity was observed in concentrated (1:1 dilution), anaerobic suspensions (up to 25-30 days). Oviductal oocytes placed in SAR at 5, 10, 15, 20 and 25 degrees C immediately after ovulation lost viability when cooled rapidly to 5 degrees C and stored for 2 h. However, oocytes retained viability for up to 8 h at the optimum storage temperature of 15 degrees C. Thus, it is concluded that during short-term storage spermatozoa retain viability for longer than oocytes, and that spermatozoa in suspensions retain viability for longer than spermatozoa stored in situ in excised testes.  相似文献   
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This paper outlines the method used in Northern Ireland to finance the generation of electricity from renewable sources in general and wind power in particular.  相似文献   
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Details are given of a new thermal-transmission apparatus which is automatic in operation, which does not depend on the measurement of a heat flux, and which requires no guard plates to eliminate edge heat losses.

The apparatus works on the principle that for conductors in series with respect to direction of heat flow, the ratio of the temperature drop across them equals the ratio of their thermal resistances, and the only measurements involved are those of temperature in the equilibrium state.

The apparatus is suitable for testing the thermal-transmission properties of textile materials up to at least 1 in. thick. Data are presented for the thermal-transmission properties of timber and of plate glass determined with the new apparatus.  相似文献   
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Research has shown that people with broken skin can be at serious risk of cross infection. A study was undertaken to assess the relative benefits of wearing vinyl, latex and plastic gloves during invasive procedures.  相似文献   
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We argue that formal analysis tools for security protocols are not achieving their full potential, and give only limited aid to designers of more complex modern protocols, protocols in constrained environments, and security APIs. We believe that typical assumptions such as perfect encryption can and must be relaxed, while other threats, including the partial leakage of information, must be considered if formal tools are to continue to be useful and gain widespread, real world utilisation. Using simple example protocols, we illustrate a number of attacks that are vital to avoid in security API design, but that have yet to be modelled using a formal analysis tool. We seek to extract the basic ideas behind these attacks and package them into a wish list of functionality for future research and tool development.  相似文献   
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